Extraction of humic acid and related materials from carbonaceous raw materials such as humalite, leonardite, sub-bituminous coal, menefee, peat, and the like has been practiced for years and is accordingly known in the art. Process steps vary, but the process output is generally a particulate material with suboptimal solubility in water.
It is known that humic substances (HS) include fulvic acid, humic acid, and/or humin. Of these, fulvic acid has the lowest molecular weight and least resistance to decomposition by microorganisms; humin has the highest molecular weight and greatest resistance to decomposition, because it has a large number of negative charges per unit mass, humin also has a very high CEC. The large molecules of humus bind to clay particles and greatly increase aggregate formation and stability therefore improving soil properties. Humin is the alkali (and acid) insoluble portion of HS that many manufacturers dispose of, although it is known that there are individuals who may extract and use it.
Since it takes longer for dry lignite to be broken down, and thus be functional in the soil, it is necessary to convert the lignite into forms that provide a more timely overall benefit (e.g. transformation into a water-soluble form). Such a conversion “unrolls” the tight molecular ball of lignite and creates water-soluble humic acids, either as a liquid or in the form of sodium, potassium, or ammonium salts (known as humates). Such a water-soluble form is desirable, as in their soluble form, humic acids can readily chelate nutrients, preserve nitrates from leaching, enhance root development, and improve overall crop vigor and yields.
Attempts to create a fully water-soluble granule enriched in humic acid have been unsuccessful. It is known that there are humic acid enriched granules that have solubility as high as about 85%, but even these are not fully water-soluble. For example, granules such as those discussed in CN 102898254. The raw humic materials undergo chemical reactions prior to granulating, in CN 102898254, but even with that the granule itself contains other insoluble portions, thus preventing the granule from achieving a full water solubility.
Suboptimal solubility in water of particulate material enriched in humic acid and related materials presents a problem. Because organic and other producers typically prefer to apply mixtures that contain solvents such as water that are safe and healthful for both plants and workers, there is a need, long-felt by now, for a process for making a fully water-soluble granule enriched in humic acid.